memo on wbdiff: "TAKE QUARTZ OUT BEFORE HF!!"

Dear All:
I see a memo attached to wbdiff, and it says: "TAKE QUARTZ OUT BEFORE HF!!"
I checked , and there is nothing in HF bath, and could not find any comment on coral regarding this memo.
Did someone drop his/her sample in the HF bath??
Thanks,
Ju Hyung